NAD and Brain Health: What Human Studies Can Tell Us

Updated October 25, 2026 · Sources linked below

NAD is involved in cellular metabolism, including in the nervous system. That biological role makes it an interesting research target. It does not, by itself, show that an NAD infusion improves memory, prevents dementia, or treats a neurological disease.

Separate the molecule from the intervention

Research may study NAD itself, a precursor such as nicotinamide riboside (NR), or another way to alter the pathway. Oral and intravenous products have different delivery methods and safety considerations. A finding from one cannot simply be presented as evidence for another.

In the small 2022 NADPARK trial, oral NR was studied in people with Parkinson disease, including changes in brain NAD-related measures. This was an early investigation, not proof of improved cognition in healthy adults. [1]

Clinical outcomes matter more than a promising marker

A larger 2026 trial, NOPARK, did not show benefit on its primary clinical outcome in early Parkinson disease. That finding should be considered alongside earlier biomarker research. Neither trial establishes a benefit from NAD IV for routine brain optimization. [2]

A useful report explains what was measured: a laboratory signal, a symptom score, everyday function, or disease progression. “Supports brain health” is too vague to tell a patient which of these, if any, has been demonstrated.

IV delivery adds separate safety questions

FDA has warned about unsuitable ingredients used in sterile compounding and reported adverse events after NAD+ injections, including severe chills, shaking, vomiting, and fatigue. These reports warrant attention even when a product is described as natural. [3]

Questions for your clinician

• Is the evidence about an infusion or an oral precursor?
• Did participants resemble me, and what outcome improved?
• What are the product-quality and infusion risks?
• Does a new memory concern need a diagnostic evaluation before a wellness intervention?

New cognitive symptoms deserve an appropriate medical assessment. An infusion should not substitute for investigating their cause.

Sources and further reading

1. Brakedal et al. NADPARK phase I randomized trial. Cell Metabolism, 2022
2. NOPARK randomized clinical trial: nicotinamide riboside in early Parkinson disease. JAMA, 2026
3. FDA: ingredients suitable for sterile compounding and NAD+ injection adverse-event reports

Patient education from OlympusMD Wellness in Milton, Georgia. This article provides general information and does not replace an individual medical evaluation.